He wasn't kidding - they adored her. We were not long in the ocean before several large mantas glided through the brightly lit water to our flotation device - an old surfboard. Snorkel, vest and fins attached, we held on to small handles on the side of the board, drifted out and looked down. As luck would have it, the pregnant woman was right next to me. It ended up being the best seat in the house.
Mantas are completely harmless, though they don't look it. Their huge size, sleek shape and gaping mouths make you nervous at the thought of entering the water. Fortunately, they're not interested in tourists - they visit the shallows of Keauhou Bay on the west coast of Hawaii's Big Island for the plankton. The lights from the diving boats and nearby Sheraton Kona attract plankton and the rays are there for a feeding frenzy. Unfortunately it can turn into a bit of a tourist frenzy too, with excited snorkellers screaming when the rays come close. We stayed calm and many a manta performed underwater ballet beneath us.
Having thought I'd mastered my emotions after coming face to face with a few of these majestic creatures, the sight of the aptly named giant female Big Bertha had me whimpering into my snorkel. Bertha decided to do 360s right below me, brushing her huge torso against mine as her 5m wingspan propelled her through the water. The short journey back to the pier was tranquil, all of us absorbing the experience as we sailed into the cool breeze coming off Hualalai volcano.
The next morning we hit the water again, this time on a charter boat. Humdinger Sportfishing Charters picked me up at the crack of dawn to hunt big fish. Once we were in deep enough water the lines went out via an outrigger set-up. As we trawled the waters to the west of Kona you could see the immense scale of the island, which is bigger than all of the other Hawaiian islands combined and has a highest point of 4207m.
The warm waters are popular with marlin, tuna and mahi-mahi, but this was a day that required patience. Then it happened. Something got hooked. Brett, the first mate, jumped into action. I watched in astonishment as the huge blue marlin breached, catapulting itself into the air before diving again. My camera wasn't ready but my eyes caught the stunning sight, etching it into my memory. That was all I caught that day however, the marlin broke free and disappeared as quickly as it came. I might've come home empty-handed but technically most people do - marlin are typically tagged and released. GPS tags have revealed marlins caught here can go as far afield as Tahiti.
After all the water sports I wasn't interested in going too much further that day, just enough to learn a little about this historic part of Hawaii. Sian from Photo Safari Hawaii was the man for the task. The first stop was for coffee - something that Kona is world famous for. The Coffee Shack in an area called Captain Cook in southern Kona was just the spot for a hot brew. Literally a shack, the dining room and deck overlooks the shoreline at more than 400m above sea level.
While sipping the smooth coffee grown on the slopes just below, you can see Kealakekua Bay, where Captain Cook arrived in Hawaii. Unfortunately it was also to be the last place he arrived - the famous explorer was killed weeks later following a quarrel with locals.
From down at the water you can see the monument erected in Cook's honour across the bay. Unreachable by road, it stands alone in a calm bay frequented by spinner dolphins. Being shown the perfect spot to take a photo accompanied by accounts of the events that shaped the area was a great way for a photo enthusiast to spend an afternoon.
The Sheraton Kona's cultural tour that followed told the story of Keauhou Bay. The tour showed the respectful relationship between the hotel and the locals, backed by cultural events that are held there.
Sitting in the open air on the balcony of the Sheraton's aptly named restaurant, Rays on the Bay, I admired the effort required by the chef to create the line-caught ahi (tuna) dish and enjoyed the view of the seemingly infinitely setting sun. Just metres away I watched my manta ray friends perform their somersaults and enjoy their own meal of plankton, surrounded by a new batch of excited tourists.
I sat back in my seat and calmly watched the scene unfold.